Generally, in the work machine such as the crawler dozer, a bracket is fixed at a plurality of positions on a vehicle body frame, and a cab frame is supported on the bracket. A damper is interposed between each of the brackets and the cab frame, and a vibration and an impact transmitted to the cab frame are damped by the damper. In each of the dampers, there is installed a movement limiting mechanism for limiting a movement of the cab frame in a vertical direction, a front-rear direction, and a lateral direction. Further, when a great load is applied to the cab frame from the outside in the case that the work machine rolls over by any chance, the movement of the cab frame in the vertical direction or the like is limited within a predetermined range by the movement limiting mechanism.
However, in the cab supporting apparatus having the structure mentioned above, since the movement limiting mechanism is installed in each of the dampers as mentioned above, the structure of the damper is complicated, and each of the dampers is enlarged in size, so that a cost required for installing the cab supporting apparatus is significantly increased.
In view of the problem mentioned above, there has been conventionally proposed a cab supporting apparatus of a work machine in which a damper and a movement limiting mechanism are arranged at different positions.
In this conventional cab supporting apparatus, since the movement limiting mechanism is provided independently from the damper, it is possible to achieve a downsizing of a damper and a simplification of an internal structure thereof. However, since the damper and the movement limiting mechanism are independent, brackets therefor may be provided independently. In such a case, the structure of the entire cab supporting apparatus becomes complicated, and a wide installing space for the cab supporting apparatus is required.
For the purpose of simplifying the structure of the cab supporting apparatus, a cab supporting apparatus is proposed in Patent Document 1. In the cab supporting apparatus of Patent Document 1, a cab frame is supported to a vehicle body frame with a damper. Further, as shown in FIG. 21, a movement limiting mechanism 103 for limiting a movement in a vertical direction or the like of a cab frame 102 is provided between a bracket 101 at one position on a vehicle body frame 109 and the cab frame 102 so as to be adjacent to a damper 104. This movement limiting mechanism 103 is provided with a shaft member 105 protruded on a lower surface of the cab frame 102, a cylindrical spacer 106 outside fitted to the shaft member 105, a stopper 107 fixed to a lower end of the spacer 106, and a supporting plate 108 arranged in a side of the bracket 101 in correspondence to the stopper 107.
Further, in the case that the cab frame 102 is moved in a direction away from the vehicle body frame 109, that is, upward in FIG. 14, the stopper 107 is brought into contact with the supporting plate 108, whereby the movement to the upper portion of the cab frame 102 is limited within a predetermined range. In contrast, in the case that the cab frame 102 is moved in a direction toward the vehicle body frame 109, that is, downward in FIG. 21, a bottom plate lower surface of the cab frame 102 is brought into contact with the upper surface of the damper 104, whereby the downward movement of the cab frame 102 is limited within a predetermined range.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2004-189089